Structure elucidation of C80, C81 and C82 isoprenoid tetraacids responsible for naphthenate deposition in crude oil production

Abstract

A series of C₈₀ isoprenoid 20-bis-16,16′-biphytanyl tetraacids has previously been found to be responsible for calcium naphthenate scaling in crude oil processing. This paper describes the structure elucidation by high-field NMR spectroscopy of the structures of the series of homologous C₈₀ tetraacids containing 4–8 five-membered rings. In addition, the structures of methyl-substituted C₈₁ and C₈₂ analogues containing 7 and 8 five-membered rings have been determined for the first time. The biosynthetic implications are discussed.